Prepared under the auspices of the Radiation Commission of the International Association of the Meteorology and Atmospheric Physics, this reference standard will provide essential information not only for researchers but also at the undergraduate level. Part I deals with the plane-parallel atmospheres and introduces four additional methods to the literature. Part II deals with non-plane parallel geometry, including horizontal inhomogeneities (finite clouds, homogeneous ground), spherical planetary atmospheres and searchlight (or laser) illumination